Island



(No Model.) 2 Sheets-Sheet l.

J. G.. TAPT. DIE" FOR THE MANUFACTURE OF TWIST DRILLS. No. 518,205, Patented Apr. 10-, 1894.

(No Model.) "2 Sheets-Sheet 2.

- J. c.- TAPT-w DIE FOR THE MAjN-UFAUTURE OF TW'IST 'DRILLS.

No. 518,205. Patented Apr. 10,1894.

nnnnnnnnnnnnn 0.

UNITED STATES PATENT OFFICE.

JEROME O. TAFT, OF PROVIDENCE, RHODE ISLAND.

DIE FOR THE MANUFACTURE OF TWIST-D RILLS.

SPECIFICATION forming part of Letters Patent No. 518,205,.dated April 10, 1894.

Application filed January 23,1893. Serial No. 459,481- (No model.) I

T0 at whom it may concern:

Be it known that I, JEROME O. TAFT, a citizen of the United States, residing at Providence, in the State of Rhode Island, have invented anew and useful Improvement in Dies for the Manufactureof Twist-Drills, of which the following is a specification.

The nature of my invention consists in the improved construction of the dies employed for twisting the previously grooved drill blank, as hereinafter fully set forth.

Figure 1, represents a side view of the grooved drill blank, as prepared for twisting. Fig. 2, represents a side view of the twisted drill. Fig. 3, represents a side view of the drill blank in process of twisting, one of the side supporting dies being removed in order to illustrate the action of the twisting dies. Fig. 4, represents a section taken in the line 2, z, of Fig. 3, but with the twisting dies in a horizontal, instead of a vertical position. Fig. 5, represents a side View of one of the twisting dies. Fig. 6, represents a face view of the same. Fig. 7, represents a side view, and Fig. 8, a face view, of one of the supporting dies. Fig. 9, represents a face view of a rotary swaging machine provided with my improved twisting dies, the front plate of the machine being removed to show the dies.

In the accompanying drawings, A represents the drill blank, which is provided with opposite straight grooves b, and A, represents the same when twisted to form the drill. The twisting dies B, are formed with a working face a, having two projecting lobes 0,0, which are adapted to act upon the opposite edges of the groove b, of the blank, while at the same time the bottom of the groove, 0r axial line of the drill between the lobes, will be unacted upon, thus producing the required uniform twist in the blank, without straining the metal at the center of the'drill; and while the lobes of each die actin the grooves, longitudinally, at opposite sides of the axial line, the corresponding lobes of the opposite dies also act, transversely, upon opposite sides of the said line. The supporting dies 0 are provided with the projecting portions 6, e, e, e, which are adapted to guide the blank to a central position for receiving the action of the twisting dies, the said twisting dies being arranged to enter the space d be tween the projections e, e, so that when the said twistingdies are brought together, the forward edge of the drill will be operated upon by the side supporting dies, as shown in Fig. 4, to provide the required sharp forwar corner, at the edge of the drill,

A rotary swaging machine in which my improved twisting dies may be employed, is shown in Fig. 9, the drill blank being in this case caused to rotate with the dies, the said dies being attached to the die holders D, D, D, D, held in the rotating head G, and operated for action upon the drill blank by engagement with the stationary boaters E, E, E, E, which are made adjustable by means of the screws F. The twisting dies may also be employed in a swaging machine in which the boaters are made to revolve, while the die holding head G is made stationary, and the twisting dies may be used either with or without the side supporting dies; and instead of being made integral, they may be made in two parts, as indicated by the dotted line f in Fig. 5.

I claim as my invention 1. The opposite twisting dies, provided upon their faces with the lobes adapted to strike, longitudinally, in the grooves of the 'blank, at opposite sides of the axial line of the drill, and not upon the said axial line, the lobes of one die, also striking, transversely, on the opposite side of the axial line, from that acted upon by the corresponding lobes of the opposite die.

2. The combination with the twisting dies provided with the lobes adapted to strike in the groove of the blank at the opposite side of the axial line of the drill, of the side supporting dies adapted to operate upon the forward corner of the blank, substantially as described.

3.. The combination with the twisting dies provided upon their faces with the lobes adapted to strike in the groove of the blank at opposite sides of the axial line of the drill, of the side supporting dies provided with the projecting portions, which serve as a guide for the blank, substantially as described.

\ JEROME C. TAFT.

Witnesses:

SOCRATES SoHoLFIELD, CHARLES F. SoHMnLz. 

